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Discussion Starter #1
Ahh yes the good old stumble fix...once again

Ok so the reasoning for me to bring this up is that im looking...more or less for a quicker cheaper fix. (leased so definitely cannot tune)

I know I can do the fuel line extension, but from my understanding I will need some sort of tune with this route?

I also managed to stumble upon someone using the GD FPR, they say it helps resolve the problem but I couldn't find a lot of information on it (does it work, tuning needed?). So if someone could shed some information on this it would be great help

And lastly IAP makes a "GR stumble fuel kit fix" for $199 which doesn't bother me, but if one of the above is going to do the trick then ill just go with that.

Have any of you guys done any of these? what were your thoughts?

These are pretty much my only three options when it comes to an easy/cheap fix that can be returned to stock in a hurry if something were to go wrong.

Thanks in advance guys any help at all is definitely appreciated.
 

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I chased the dreaded stumble for over a year with two different tuners. I tried the fuel line extension, changing to the GD regulator set-up, an aftermarket regulator, and at least half a dozen tuning tweaks along the way to try to get rid of it. Replacing the fuel rails was what solved it 100%.

Essentially, changing the rails treated the disease, everything else was treating the symptoms. Other people may have had better luck with the cheaper changes, but for my car none of them worked out.
 

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Personally, I've done the fuel extension mod and it works very well. If you have an accessport and ots map, you can ask Cobb for AccessTuner for free and modify the ECU yourself. It's very easy and only involves changing 2 parameters. As for the latter 2 options, I don't have experience with them and cannot say much.
 

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Discussion Starter #4
did you guys run any of these remedies at all before adjusting your maps, what results were yielded?

What are the dangers associated with me not tuning after I do the mods?

I apologize if I was unclear in the previous post, I am on a lease and cannot tune until my buyout period arrives. This is more or less for me to tame the problem down, so if something were to go bad with my motor I could easily just return it back to the way it was.

Thanks for the input, good information so far!
 

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I just ran 3' of Fuel Injector Hose and called it a day. $10 and I was in business. No tune, no more stumble except if I recently pulled the battery which resets the ECU. After a couple drive cycles it seems to smooth itself out.

Word of advice: use a drop of blue service removable loctite on the hose clamp screw, otherwise it may back out over time.
 

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Discussion Starter #6
I just ran 3' of Fuel Injector Hose and called it a day. $10 and I was in business. No tune, no more stumble except if I recently pulled the battery which resets the ECU. After a couple drive cycles it seems to smooth itself out.

Word of advice: use a drop of blue service removable loctite on the hose clamp screw, otherwise it may back out over time.

did you use the same method and hose used in this writeup: http://www.iwsti.com/forums/how-install/254372-fuel-line-extension-stumble-fix-mod.html
 

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Discussion Starter #9
$25.00 later..got the hose and clamps!

now all i need is for spring to come, and for the snow to melt so i can get the whip back on the road. Ill be dropping a post once i get a few runs in on it.

Thanks for the help once again boys, If theres any other tips, tricks, or wisdom to be given just list them here for some other noob such as myself!
 

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Discussion Starter #13
I'm no expert, but my tuner told me parameter adjustment was mandatory after installing the fuel extension mod. He made the adjustments free of charge, so it wasn't about making a profit.
This is what scares me, I've seen a few people say that they suggest a tune and that its "possible" for issues to surface. That being said I have never actually seen someone post a failure directly due to the mod.
 

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This is what scares me, I've seen a few people say that they suggest a tune and that its "possible" for issues to surface. That being said I have never actually seen someone post a failure directly due to the mod.
From time to time, you're going to see things such as that here. I asked a question awhile back about if a DP with a cat near the bellmouth will scorch/burn the passenger CV boot. I never got a definitive answer or saw a legit fix and I asked multiple times. It's frustrating, because you have some guys that post-whore all over the damned forum about anything, then when an important question is posted, the post has little to no response (or contradicting answers).

You've several choices: 1) do the fix then get a tune; 2) consult a reputable shop; 3) hold off with your mod until you've a definitive answer on if a tune is needed or not; 4) go ahead with your mod since many people have done the mod with no bad results. As well, I'd ask this question on different Subaru boards just to ensure you get as much 'press' as possible...that might help in getting some solid information.
 

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Discussion Starter #15
From time to time, you're going to see things such as that here. I asked a question awhile back about if a DP with a cat near the bellmouth will scorch/burn the passenger CV boot. I never got a definitive answer or saw a legit fix and I asked multiple times. It's frustrating, because you have some guys that post-whore all over the damned forum about anything, then when an important question is posted, the post has little to no response (or contradicting answers).

You've several choices: 1) do the fix then get a tune; 2) consult a reputable shop; 3) hold off with your mod until you've a definitive answer on if a tune is needed or not; 4) go ahead with your mod since many people have done the mod with bad results. As well, I'd ask this question on different Subaru boards just to ensure you get as much 'press' as possible...that might help in getting some solid information.
I agree 100% with you, some very valid and useful information right here.

ill do a few more posts on some other forums and do some asking around. Ill let you guys know what I come back with.

Thanks for the help
 

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Mark, the fuel line extension alone will either work for you, or it won't. It won't do any harm if you don't change the tune. Without the tune adjustment, you will run a bit rich in a certain rpm/load zone. That's all.

Frank
 

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Discussion Starter #17
Mark, the fuel line extension alone will either work for you, or it won't. It won't do any harm if you don't change the tune. Without the tune adjustment, you will run a bit rich in a certain rpm/load zone. That's all.

Frank
Thanks frank, im thinking ill hook it up for a few runs see how the car reacts.

I posted these same questions up on nasioc...it turned into a bloody battlefield between two dudes, hopefully ill get some decently useful info soon.
 

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Thanks frank, im thinking ill hook it up for a few runs see how the car reacts.

I posted these same questions up on nasioc...it turned into a bloody battlefield between two dudes, hopefully ill get some decently useful info soon.

That's NASIOC for ya :lol:
 

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I did the stumble fix and immediately got on the e-tune bandwagon. Eric at TP actually said it was mandatory before he would touch the tune. So far I have not experienced any more stumble.
 

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I chased the dreaded stumble for over a year with two different tuners. I tried the fuel line extension, changing to the GD regulator set-up, an aftermarket regulator, and at least half a dozen tuning tweaks along the way to try to get rid of it. Replacing the fuel rails was what solved it 100%.

Essentially, changing the rails treated the disease, everything else was treating the symptoms. Other people may have had better luck with the cheaper changes, but for my car none of them worked out.
Hit the nail on the head ! :tup:
 
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